libio/vswprintf.c

   1 /* Copyright (C) 1994,1997,1999-2002,2004 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.
  18
  19    As a special exception, if you link the code in this file with
  20    files compiled with a GNU compiler to produce an executable,
  21    that does not cause the resulting executable to be covered by
  22    the GNU Lesser General Public License.  This exception does not
  23    however invalidate any other reasons why the executable file
  24    might be covered by the GNU Lesser General Public License.
  25    This exception applies to code released by its copyright holders
  26    in files containing the exception.  */
  27
  28 #include "libioP.h"
  29 #include "strfile.h"
  30
  31
  32 typedef struct
  33 {
  34   _IO_strfile f;
  35   /* This is used for the characters which do not fit in the buffer
  36      provided by the user.  */
  37   wchar_t overflow_buf[64];
  38 } _IO_strnfile;
  39
  40
  41 static wint_t _IO_wstrn_overflow __P ((_IO_FILE *fp, wint_t c));
  42
  43 static wint_t
  44 _IO_wstrn_overflow (fp, c)
  45      _IO_FILE *fp;
  46      wint_t c;
  47 {
  48   /* When we come to here this means the user supplied buffer is
  49      filled.  But since we must return the number of characters which
  50      would have been written in total we must provide a buffer for
  51      further use.  We can do this by writing on and on in the overflow
  52      buffer in the _IO_strnfile structure.  */
  53   _IO_strnfile *snf = (_IO_strnfile *) fp;
  54
  55   if (fp->_wide_data->_IO_buf_base != snf->overflow_buf)
  56     {
  57       INTUSE(_IO_wsetb) (fp, snf->overflow_buf,
  58                          snf->overflow_buf + (sizeof (snf->overflow_buf)
  59                                               / sizeof (wchar_t)), 0);
  60
  61       fp->_wide_data->_IO_write_base = snf->overflow_buf;
  62       fp->_wide_data->_IO_read_base = snf->overflow_buf;
  63       fp->_wide_data->_IO_read_ptr = snf->overflow_buf;
  64       fp->_wide_data->_IO_read_end = (snf->overflow_buf
  65                                       + (sizeof (snf->overflow_buf)
  66                                          / sizeof (wchar_t)));
  67     }
  68
  69   fp->_wide_data->_IO_write_ptr = snf->overflow_buf;
  70   fp->_wide_data->_IO_write_end = snf->overflow_buf;
  71
  72   /* Since we are not really interested in storing the characters
  73      which do not fit in the buffer we simply ignore it.  */
  74   return c;
  75 }
  76
  77
  78 static const struct _IO_jump_t _IO_wstrn_jumps =
  79 {
  80   JUMP_INIT_DUMMY,
  81   JUMP_INIT(finish, _IO_wstr_finish),
  82   JUMP_INIT(overflow, (_IO_overflow_t) _IO_wstrn_overflow),
  83   JUMP_INIT(underflow, (_IO_underflow_t) _IO_wstr_underflow),
  84   JUMP_INIT(uflow, (_IO_underflow_t) INTUSE(_IO_wdefault_uflow)),
  85   JUMP_INIT(pbackfail, (_IO_pbackfail_t) _IO_wstr_pbackfail),
  86   JUMP_INIT(xsputn, INTUSE(_IO_wdefault_xsputn)),
  87   JUMP_INIT(xsgetn, INTUSE(_IO_wdefault_xsgetn)),
  88   JUMP_INIT(seekoff, _IO_wstr_seekoff),
  89   JUMP_INIT(seekpos, _IO_default_seekpos),
  90   JUMP_INIT(setbuf, _IO_default_setbuf),
  91   JUMP_INIT(sync, _IO_default_sync),
  92   JUMP_INIT(doallocate, INTUSE(_IO_wdefault_doallocate)),
  93   JUMP_INIT(read, _IO_default_read),
  94   JUMP_INIT(write, _IO_default_write),
  95   JUMP_INIT(seek, _IO_default_seek),
  96   JUMP_INIT(close, _IO_default_close),
  97   JUMP_INIT(stat, _IO_default_stat),
  98   JUMP_INIT(showmanyc, _IO_default_showmanyc),
  99   JUMP_INIT(imbue, _IO_default_imbue)
 100 };
 101
 102
 103 int
 104 _IO_vswprintf (string, maxlen, format, args)
 105      wchar_t *string;
 106      _IO_size_t maxlen;
 107      const wchar_t *format;
 108      _IO_va_list args;
 109 {
 110   _IO_strnfile sf;
 111   int ret;
 112   struct _IO_wide_data wd;
 113 #ifdef _IO_MTSAFE_IO
 114   sf.f._sbf._f._lock = NULL;
 115 #endif
 116
 117   if (maxlen == 0)
 118     /* Since we have to write at least the terminating L'\0' a buffer
 119        length of zero always makes the function fail.  */
 120     return -1;
 121
 122   _IO_no_init (&sf.f._sbf._f, _IO_USER_LOCK, 0, &wd, &_IO_wstrn_jumps);
 123   _IO_fwide (&sf.f._sbf._f, 1);
 124   string[0] = L'\0';
 125   _IO_wstr_init_static (&sf.f._sbf._f, string, maxlen - 1, string);
 126   ret = _IO_vfwprintf ((_IO_FILE *) &sf.f._sbf, format, args);
 127
 128   if (sf.f._sbf._f._wide_data->_IO_buf_base == sf.overflow_buf)
 129     /* ISO C99 requires swprintf/vswprintf to return an error if the
 130        output does not fit int he provided buffer.  */
 131     return -1;
 132
 133   /* Terminate the string.  */
 134   *sf.f._sbf._f._wide_data->_IO_write_ptr = '\0';
 135
 136   return ret;
 137 }
 138
 139 #ifdef weak_alias
 140 weak_alias (_IO_vswprintf, __vswprintf)
 141 weak_alias (_IO_vswprintf, vswprintf)
 142 #endif